On 3/31/23 06:58, Camelia Alexandra Groza wrote:

quoted

-----Original Message-----
From: Sean Anderson <redacted>
Sent: Monday, March 27, 2023 22:29
To: Leo Li <redacted>; linuxppc-dev@lists.ozlabs.org; linux-arm-
kernel@lists.infradead.org
Cc: Scott Wood <oss@buserror.net>; linux-kernel@vger.kernel.org; David S .
Miller [off-list ref]; Claudiu Manoil [off-list ref];
Roy Pledge [off-list ref]; Vladimir Oltean
[off-list ref]; Camelia Alexandra Groza
[off-list ref]; Sean Anderson [off-list ref]
Subject: [PATCH 1/2] soc: fsl: qbman: Always disable interrupts when taking
cgr_lock

smp_call_function_single disables IRQs when executing the callback. To
prevent deadlocks, we must disable IRQs when taking cgr_lock elsewhere.
This is already done by qman_update_cgr and qman_delete_cgr; fix the
other lockers.

Fixes: c535e923bb97 ("soc/fsl: Introduce DPAA 1.x QMan device driver")
Signed-off-by: Sean Anderson <redacted>
---

 drivers/soc/fsl/qbman/qman.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
index 739e4eee6b75..ff870ca07596 100644
--- a/drivers/soc/fsl/qbman/qman.c
+++ b/drivers/soc/fsl/qbman/qman.c

@@ -1456,7 +1456,7 @@ static void qm_congestion_task(struct work_struct

*work)
 	union qm_mc_result *mcr;
 	struct qman_cgr *cgr;

-	spin_lock(&p->cgr_lock);
+	spin_lock_irq(&p->cgr_lock);
 	qm_mc_start(&p->p);
 	qm_mc_commit(&p->p, QM_MCC_VERB_QUERYCONGESTION);
 	if (!qm_mc_result_timeout(&p->p, &mcr)) {

@@ -1476,7 +1476,7 @@ static void qm_congestion_task(struct work_struct

*work)
 	list_for_each_entry(cgr, &p->cgr_cbs, node)
 		if (cgr->cb && qman_cgrs_get(&c, cgr->cgrid))
 			cgr->cb(p, cgr, qman_cgrs_get(&rr, cgr->cgrid));
-	spin_unlock(&p->cgr_lock);
+	spin_unlock_irq(&p->cgr_lock);
 	qman_p_irqsource_add(p, QM_PIRQ_CSCI);
 }

There is one more spin_unlock call in qm_congestion_task on the error path that needs updating:

if (!qm_mc_result_timeout(&p->p, &mcr)) {
	spin_unlock(&p->cgr_lock);

Will fix. Thanks.

--Sean

quoted

@@ -2440,7 +2440,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32

flags,
 	preempt_enable();

 	cgr->chan = p->config->channel;
-	spin_lock(&p->cgr_lock);
+	spin_lock_irq(&p->cgr_lock);

 	if (opts) {
 		struct qm_mcc_initcgr local_opts = *opts;

@@ -2477,7 +2477,7 @@ int qman_create_cgr(struct qman_cgr *cgr, u32

flags,
 	    qman_cgrs_get(&p->cgrs[1], cgr->cgrid))
 		cgr->cb(p, cgr, 1);
 out:
-	spin_unlock(&p->cgr_lock);
+	spin_unlock_irq(&p->cgr_lock);
 	put_affine_portal();
 	return ret;
 }
--
2.35.1.1320.gc452695387.dirty